CN-122029003-A - Seeking substrate grooves on a substrate between lands in chemical mechanical polishing

Abstract

The groove detection station includes a sensor for generating a signal that depends on the proportion of the sensing area of the sensor that is covered by the substrate, and a controller. The controller is configured to position the carrier head relative to the sensor such that the sensing region of the sensor is located at an edge of the substrate, to cause rotational movement of the motor such that the sensing region of the sensor scans along a circumference of the substrate, and to detect an angular position of a groove in the edge of the substrate based on a signal from the sensor, including compensating for a sinusoidal component of the signal resulting from the substrate center being offset from the axis of rotation.

Inventors

• N. Moda medi
• D.J. Benwegnu
• B.A. Swedek
• H.Q.Li
• S.M. Sunica
• J.H.K.Huang

Assignees

• 应用材料公司

Dates

Publication Date

20260512

Application Date

20240918

Priority Date

20230929

Claims (20)

1. 1. A polishing apparatus, the polishing apparatus comprising: a plurality of stations including a first station that is a polishing station or a transfer station and a second station that is a polishing station; A carrier head for holding a substrate, the carrier head being movable by an actuator along a path from the first station to the second station; a motor for rotating the carrier head about an axis of rotation; A groove detection station positioned on the path between the first station and the second station, the groove detection station including a sensor for generating a signal according to a proportion of a sensing area of the sensor covered by the substrate, and A controller configured for Positioning the actuator to the carrier head to position the substrate at the groove detection station, positioning a sensing region of the sensor at an edge of the substrate, Rotating the motor to rotate the carrier head so that the sensing region of the sensor scans along the circumference of the substrate, and Detecting the angular position of a groove in an edge of the substrate from a signal emitted by the sensor includes compensating for a sinusoidal component of the signal resulting from the center of the substrate being offset from the axis of rotation.
2. 2. The apparatus of claim 1, wherein the sensor comprises an optical sensor comprising a light source for generating a light beam striking a surface of the substrate and a detector for detecting reflected light and generating a signal indicative of the intensity of the reflected light.
3. 3. The apparatus of claim 2, wherein the optical sensor is configured at an oblique angle.
4. 4. The apparatus of claim 2, wherein the optical sensor is configured to generate a light beam that impinges on and is perpendicular to a surface of the substrate.
5. 5. The apparatus of claim 2, wherein the light source comprises a laser.
6. 6. The apparatus of claim 2, wherein the light source comprises a plurality of light sources that produce light beams having different wavelengths.
7. 7. The apparatus of claim 6, wherein the controller is configured to select a light source from the plurality of light sources according to a pattern on the substrate.
8. 8. The apparatus of claim 1, wherein the sensor comprises a capacitive sensor.
9. 9. The apparatus of claim 1, wherein the sensor comprises a confocal microscope.
10. 10. The apparatus of claim 1, wherein the sensor comprises a laser displacement sensor.
11. 11. The apparatus of claim 1, wherein the first station is a polishing station.
12. 12. The apparatus of claim 1, wherein the first station is a transmitting station.
13. 13. The device of claim 1, wherein the controller is configured to compensate the sinusoidal component of the signal by monitoring a first derivative of the signal and detecting that a portion of the first derivative exceeds a threshold.
14. 14. The device of claim 1, wherein the controller is configured to compensate the sinusoidal component of the signal by monitoring a second derivative of the signal and detecting a portion of the second derivative exceeding a threshold.
15. 15. The device of claim 1, wherein the controller is configured to compensate for the sinusoidal component of the signal by subtracting a sinusoidal function from the signal.
16. 16. The apparatus of claim 15, wherein the sine function is fitted to the signal prior to subtraction from the signal.
17. 17. The device of claim 1, wherein the controller is configured to compensate the sinusoidal component of the signal by applying a high pass filter to the signal that removes the sinusoidal component.
18. 18. The device of claim 1, wherein the radial width of the sensing region is 5-10 millimeters.
19. 19. The device of claim 1, wherein the sensing region is substantially circular.
20. 20. The apparatus of claim 1, wherein the controller is configured to cause the actuator to position the carrier head such that the substrate is positioned such that the sensing does not overlap a stationary ring of the carrier head.

Description

Seeking substrate grooves on a substrate between lands in chemical mechanical polishing Technical Field The present disclosure relates to detecting an angular position of a substrate, such as a position of a substrate recess, in a Chemical Mechanical Polishing (CMP) system. Background Integrated circuits are typically formed on a substrate by sequentially depositing conductive, semiconductive, or insulative layers on a silicon wafer. One of the fabrication steps is to deposit a filler layer on a non-planar surface and planarize the filler layer. For some applications, the filler is planarized until the top surface of the patterned layer is exposed. For example, a conductive filler layer may be deposited on the patterned insulating layer to fill the trenches or holes in the insulating layer. After planarization, the portions of the metal layer remaining between the raised patterns of the insulating layer form vias, plugs, and fine lines that provide conductive paths between thin film circuits on the substrate. For other applications, such as oxide polishing, the filler layer may be planarized until a predetermined thickness is left on the non-planar surface. In addition, photolithography generally requires planarization of the substrate surface. Chemical Mechanical Polishing (CMP) is a well-known planarization method. Such planarization methods typically require the substrate to be mounted on a carrier or polishing head. The exposed surface of the substrate is typically placed on a rotating polishing pad. The carrier head provides a controlled load on the substrate pushing it toward the polishing pad. The polishing pad surface typically will have an abrasive polishing slurry. Disclosure of Invention A polishing apparatus includes a plurality of stations including a first station and a second station, the first station being a polishing station or a transfer station, the second station being a polishing station, a carrier head for holding a substrate, the carrier head being movable along a path from the first station to the second station by an actuator, a motor for rotating the carrier head about a rotation axis, a groove detection station positioned on the path between the first station and the second station, the groove detection station including a sensor for generating a signal according to a ratio of a sensing area of the sensor covered by the substrate, and a controller. The controller is configured to position the actuator to the carrier head to position the substrate at the groove detection station, position the sensing region of the sensor at the edge of the substrate, rotate the carrier head to scan the sensing region of the sensor along the circumference of the substrate, and detect the angular position of the groove in the edge of the substrate based on the signal emitted by the sensor, including compensating for a sinusoidal component of the signal resulting from the center of the substrate being offset from the axis of rotation. In another aspect, a method includes the steps of holding a substrate in a carrier head, the substrate positioned such that a sensing region of a sensor of a groove detection station is located at an edge of the substrate, rotating the carrier head to rotate the substrate such that the sensing region of the sensor scans along a circumference of the substrate, and detecting an angular position of a groove in the edge of the substrate based on a signal from the sensor, including compensating for a sinusoidal component of the signal generated by the center of the substrate being offset from the axis of rotation. In another aspect, a groove detection station includes a sensor for generating a signal that depends on a proportion of a sensing area of the sensor that is covered by a substrate, and a controller configured to cause an actuator to position a carrier head relative to the substrate with the sensing area of the sensor at an edge of the substrate, cause a relative motion between the carrier head and the sensor to cause the sensing area of the sensor to scan along a circumference of the substrate, and detect an angular position of a groove in the edge of the substrate based on the signal from the sensor, including compensating for a sinusoidal component of the signal generated by the center of the substrate being offset from an axis of rotation. Particular embodiments may include one or more of the following potential advantages. The angular position of the substrate relative to the carrier head may be determined and the carrier head may be rotated to place the substrate recess in a desired angular position. Polishing can be performed more consistently between each wafer, thereby reducing wafer-to-wafer non-uniformity (WTWNU). In-situ monitoring may be more reliable, thereby improving intra-wafer uniformity (WIWU) and inter-wafer uniformity (WTWU). The details of one or more implementations are set forth in the accompanying drawings and the description below. Other as